The present invention is directed to a torque biasing differential for distributing torque from an input drive to first and second output shafts and, more particularly, to a torque biasing differential having coupled and compound planetary gear sets.
Torque biasing differentials are used to bias torque between driven shafts, such as axle half-shafts, in a variety of motor driven vehicles including wheel-driven automobiles and trucks, track-laying vehicles such at tanks, off-road vehicles with paired-wheel steering, and boats with twin propellers. Selectively biasing drive torque between the shafts enhances vehicle performance such as by providing steering augmentation and control of wheel slip in low traction environments. Many conventional torque biasing differentials include bevel gears in combination with planetary gear sets and torque sinks for controlling the distribution of torque. Despite the recognition in the art of the benefits of differential movement of driven shafts and the general benefits of planetary gear sets in such systems, there remains an unfulfilled need for a torque biasing differential that provides the controllable variation of speed and torque between the driven shafts in a concentric configuration that enhances packaging and minimizes the size and weight of the differential.
In view of the above, the present invention is directed to a torque biasing differential including a planetary case rotatable about an axis, a first output shaft rotatable relative to the planetary case, a second output shaft rotatable relative to the planetary case and the first output shaft, and a planetary assembly coupling the planetary case to the first and second output shafts. The planetary assembly includes first and second intermeshed inboard planet gears. The differential also include torque sinks associated with each of the first and second planetary assemblies to selectively distribute torque between the output shafts and control relative shaft rotation. The various embodiments of the torque biasing differential also describe alternative planetary differential configurations relating to the structure, orientation, and interaction of the sun gears, planet gears, and case.
Further scope of applicability of the present invention will become apparent from the following detailed description, claims, and drawings. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.